The reason to ship clubs has nothing to do with cost vs the airline baggage charges. It is to ensure your clubs are not “misplaced” and are there when you get there. You also don’t have to drag them around to and from the airport. After numerous arguments with the airlines as to where the hell are my clubs, one employee finally clued me in. He said, “the airline business is to haul passengers and not luggage”. “If you want your precious golf clubs treated importantly, then ship them”. “When shipped, they don’t ride on passengers flights that are often delayed, cancelled or subject to weight restrictions”. “They go on dedicated freight planes where any cargo is treated as same as transplant organs or expensive flowers”. “Most important, they go no where near Heathrow”. I now happily ship to avoid guys like that being in charge of my sticks.
Also, to the original question: packing yourself and shipping via fedex or other carriers is more expensive than shipsticks. Ships sticks has special carrier pricing that allows them to take a margin and get you a better deal.